//
//  QRCode.m
//  Mahjong
//
//  Created by 饶首建 on 17/6/28.
//  Copyright © 2017年 com.ikamobile.com. All rights reserved.
//

#import "QRCode.h"

@implementation QRCode

+ (UIImage*)qrCode:(float)width url:(NSString*)url{
    // 1. 实例化二维码滤镜
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 2. 恢复滤镜的默认属性
    [filter setDefaults];
    
    // 3. 将字符串转换成NSData
    NSString *urlStr = url;//测试二维码地址,次二维码不能支付,需要配合服务器来二维码的地址(跟后台人员配合)
    NSData *data = [urlStr dataUsingEncoding:NSUTF8StringEncoding];
    // 4. 通过KVO设置滤镜inputMessage数据
    [filter setValue:data forKey:@"inputMessage"];
    
    // 5. 获得滤镜输出的图像
    CIImage *outputImage = [filter outputImage];
    
    // 6. 将CIImage转换成UIImage，并放大显示 (此时获取到的二维码比较模糊,所以需要用下面的createNonInterpolatedUIImageFormCIImage方法重绘二维码)
    //    UIImage *codeImage = [UIImage imageWithCIImage:outputImage scale:1.0 orientation:UIImageOrientationUp];
    
    //重绘二维码,使其显示清晰
    return [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:width];
}
/**
 * 根据CIImage生成指定大小的UIImage
 *
 * @param image CIImage
 * @param size 图片宽度
 */
+(UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size{
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    // 1.创建bitmap;
    size_t width = CGRectGetWidth(extent) * scale;
    size_t height = CGRectGetHeight(extent) * scale;
    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
    CGContextScaleCTM(bitmapRef, scale, scale);
    CGContextDrawImage(bitmapRef, extent, bitmapImage);
    // 2.保存bitmap到图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}

@end
